Lead pigment and similar compounds.



ELMER A. SPERRY, OF BROOKLYN, NEW YORK.

LEAD PIGMENT AND SIMILAR COMPOUNDS.

. Specification ofrLetters Patent.

Patented Oct. 1. 1907:

A plication filed August 30,1906. Serial No. 332,701.

To all whom it may concern:

Be it known that I, ELMER A. SPERRY, a citizen of the United States, residing at Brooklyn, in the county of Kings and State of NewYork, have invented new and useful Improvements in the Electrolytic Production of Lead Pigments and Similar Compounds, .of

which the following is a specification.

My invention relates to an improved process of producing lead compounds or lead salts such, for instance, as are used for pigments, and it consists in the method and details of procedure set out in the following speci-. fication and particularly. pointed out in the claims hereto annexed I have disehvered that electrolysis of lead in a suitable electrolyte previous to its being subjected to the reagents necessary to the production of the various pigments or compounds, and especially where the operation goes forward in the presence of an energizing electrolyte in the same cell, and

factor such as will promote the reaction, for instance electrical as in electrolytic action, or light or heat; to repeat, such previous electrolysis fits and prepares the lead for the attack of the reagents in such a manner as to impart to the pigments or terminal product peculiar. qualities of physical structure which better fits it'for its uses. For instance, white lead produced electrolytically absorbs as high as 20 mm. (drops) of oilper gram to bring it to a standard paste, whereas by using the cathode product'of the first electrolysis as anode in the second, the particle be renderedvharder; it then works entirely different in spreading under the brush, and has other physical characteristics which are different, but probably the most distinguishing feature is that with this lead it is possible to bring oil sorption down to between 3 and 4 mm.s per gram. It should be noted in this connection that the after treatments in the two instances are identical with the same with the same current density. The important improvement of conditions in this-case are therefore due to the pre-treatment and this is found to be true with other forms of after treatment. In my first electrolysis I may employ any of 1 the well known electrolytes suitable for working with the metal.

In this connection I may name tartrate or acetate of lead as being among such electrolytes. The cathode or cathode product is then thoroughly washed and subjected to re-acting agents; thisagent may be applied in any but preferably in the presence of a reaction-promoting energizing factor. I prefer to electrolyze this cathode mass or material in an electrolyte which will produce the particular lead compound desired. For example: let us consider the production of orange mineral, one of the well known pigments,

which is usually made by oxidizing at a high temperature white lead prepared in this instance from the cathode product of the first electrolytic bath which has also been subjected to a second electrolytic treatment the product possessing great brilliancy.

,The cathode or cathode material from the first electrolysis after being washed as above stated, is taken i and without altering its nature form and constitutes the anode preferably as it stands or in some instances its element (for instance the mass being coupled to positive pole) in a second electrolytic cell employing preferably a nitrate or acetate electrotyte. For example: sodium acetate. A diaphragm is preferably used to separate the electrodes, the pigment being produced in the anolyte upon the introduction of carbonic acid gas suitably into such anolyte. The white lead thus obtained is of a very superior quality. This is washed free from the electrolyte and that portion which is to be utilized as orange mineral is then dried and subjected to an oxidizing process either in an anodic reaction in electrolytic process or ina furnace at high temperature. After the oxidation has progressed suitably the product is removed and constitutes the pigment de;

sired. This pigment thus made is of extreme purity, is high in opacity and covering povger and possesses a tinting value and brilliancy not possible in orange mineral made without the electrolysis, and this is true with other pigments prepared in accordance with the method described.

. It will be understood that the example given is simply for purposes of illustration of the manufacture of one of the lead compounds falling within the scope of the present invention which extends to the manufacture of other lead compounds. I While is is understood that the gener cedure specified may be followed, yet is not limited to such plan.

I claim:

the invention pounds of lead possessing peculiar qualities which consists in subjecting lead to electrolysis as anode in an electrolyte causing deposition 6f metallic lead at the cathode and treating the cathode product for production of the desired compound. i

2. The process of 'prcpsring a'gments and similar com pounds of lead possessing peculiar qualities which consists in subjecting lead to electrolysis as anode in an electrolyte causing deposition of metallic'lead at the cathode and then exposing the cathode product as anode in another clectro Iyte causing: depositionot' a lead compound.

The process of preparing pigments and similar 'compounds or lead possessing peculiar qualities which consists in subjecting lead to electrolysis as anode in an electrolyte causing deposition of metallic lead at the cathodc,-tlien exposing the cathode proddlit without changing its form i plan of pro- 1. The process of preparing pigments and similar com-' vated temperature thus producing: the desired terminal 10 product.

In testimony whereof I hove hereunto set my hand in presence of two subscribing witnesses.

ELMER A. SIERRY. Witnesses E. F. HUDSON, Z. A. Sriumr. 

